What it says is that Singleton is expected to do plenty of damage with his bat once he arrives in the Major Leagues, which could happen as soon as Opening Day with the Astros. The 6-foot-2, 235-pound Singleton generates impressive left-handed power, and his patience and willingness to use the whole field make him a quality hitter as well.

"He's very quiet at the plate, with a clean stroke, and the ball jumps off of his bat," Astros director of player development Quinton McCracken said. "For a young kid, he just has a presence about him. When he gets in the box, you know he's in control."

Singleton projects as a potential .280 hitter who could produce 25 homers on an annual basis. While the consensus among scouts is that he'll definitely produce at the plate, they're split on whether he stands out more for his hitting ability or his pop. Singleton doesn't have an answer either.

"To be honest, I don't know," Singleton said. "I just try to go out there and play hard. Every time I get an at-bat, I go up there and try to hit the ball as hard as I can."

Singleton first caught the eye of scouts in the summer after his sophomore season at Millikan High in Long Beach, Calif. As a 15-year-old using a wood bat, he blasted a 400-foot homer at San Manuel Stadium, home of the California League's Inland Empire 66ers. But Singleton faltered as a senior and dropped to the eighth round of the 2009 First-Year Player Draft, where he signed with the Phillies for $200,000.

Singleton seemed to relax in pro ball, and he established himself as Philadelphia's top position prospect two years into his career. In July 2011, the Phils sent him to the Astros as part of a four-player package for Hunter Pence. (That deal could pay off handsomely for Houston, which also received current big league pitchers Jarred Cosart and Josh Zeid as well as outfield prospect Domingo Santana.)

Singleton blossomed in his first full season in the Astros' Minor League organization, establishing career highs with 21 homers, a .396 on-base percentage and a .497 slugging percentage as a 20-year-old in Double-A in 2012. Then his career got put on hold.

In January 2013, Major League Baseball suspended Singleton for the first 50 games of the season for a second violation of Minor League Baseball's drug policy after he tested positive for marijuana. When he returned to the diamond, he had a tough time getting untracked at the plate. Singleton spent a week in low Class A and two weeks in Double-A before getting his first taste of Triple-A, where he batted an uncharacteristic .220/.340/.347 in 73 games.

"The entire year, I was kind of in and out of a funk because of the suspension, switching levels so much," Singleton said. "It was very, very drastic. Nonetheless, it was about making adjustments from day to day. That was the biggest issue I had."

McCracken said the Astros believe Singleton learned from his mistake and handled the punishment well. He rebounded with a strong winter in Puerto Rico, and the club still views him as every bit the prospect he was before his suspension.

"He missed a lot of at-bats this past year, and he just needs to polish his overall game offensively and defensively," McCracken said. "The strength is there, the power is there, and he has a great eye at the plate. There's some swing and miss there, and he needs to work at hitting lefties a little better, getting back those extra at-bats."

While the Astros have gone through some rough times recently, setting a franchise record for losses and finishing with the worst mark in the Major Leagues in each of the past three seasons, the farm system gives them hope. Houston has several talented prospects working their way up through the Minors. Singleton said it's exciting to think about what the future holds for the Astros.

"There's a lot of good guys in our organization, and for the most part, they all go out there and play hard and leave it all out on the field, so I'm very excited to play with some guys who are a little younger than I and coming up," Singleton said. "George Springer is a freak athlete and things come very easy to him, so it's always exciting to watch him play. Carlos Correa's a very good shortstop at a young age."

Like Springer, Singleton will compete for a starting spot with the Astros during Spring Training. At 22, he's easily the youngest first-base candidate in a group that also includes Japhet Amador, Jesus Guzman, Marc Krauss and Brett Wallace -- but Singleton also has the highest offensive upside. That's what makes him the game's top first-base prospect for the second year running, and it should make him a regular in Houston in the very near future.

Jim Callis is a reporter for MLB.com and writes a blog, Callis' Corner. Follow @jimcallisMLB on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.